Mixing
Writing Integers to stream
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I have created a library which has a portion of code similar to following
int a;
a = 5;
std::ofstream outFile("File.txt");
outFile << "Values : " << std::endl;
outFile << a << std::endl;
Now, this library is used by two different process which outputs File.txt with two different outputs
Output 1 :
Values :
Ouptut 2 :
Values :
5
I've found some resources where its mentioned to pass integers to streams by converting to strings using std::to_string (Converting integer to string in c++) . But I want to know what makes the two processes act differently in the same scenario. It feels like as if one of the process do some changes to the streams in a global state
c++ ostream
asked Jan 3 at 9:33
BAdhiBAdhi
151215
add a comment |
I have created a library which has a portion of code similar to following
int a;
a = 5;
std::ofstream outFile("File.txt");
outFile << "Values : " << std::endl;
outFile << a << std::endl;
Now, this library is used by two different process which outputs File.txt with two different outputs
Output 1 :
Values :
Ouptut 2 :
Values :
5
I've found some resources where its mentioned to pass integers to streams by converting to strings using std::to_string (Converting integer to string in c++) . But I want to know what makes the two processes act differently in the same scenario. It feels like as if one of the process do some changes to the streams in a global state
c++ ostream
asked Jan 3 at 9:33
BAdhiBAdhi
151215
2
Without a Minimal, Complete, and Verifiable example it's impossible to help you (except to wildly guess). Please take some time to review how to ask good questions, as well as this question checklist.
– Some programmer dude
Jan 3 at 9:37
2
On Linux if two processes are trying to write to same file, result is undefined. If you append PID to file-name, you will get correct output.
– gjha
Jan 3 at 9:38
add a comment |
I have created a library which has a portion of code similar to following
int a;
a = 5;
std::ofstream outFile("File.txt");
outFile << "Values : " << std::endl;
outFile << a << std::endl;
Now, this library is used by two different process which outputs File.txt with two different outputs
Output 1 :
Values :
Ouptut 2 :
Values :
5
I've found some resources where its mentioned to pass integers to streams by converting to strings using std::to_string (Converting integer to string in c++) . But I want to know what makes the two processes act differently in the same scenario. It feels like as if one of the process do some changes to the streams in a global state
c++ ostream
asked Jan 3 at 9:33
BAdhiBAdhi
151215
I have created a library which has a portion of code similar to following
int a;
a = 5;
std::ofstream outFile("File.txt");
outFile << "Values : " << std::endl;
outFile << a << std::endl;
Now, this library is used by two different process which outputs File.txt with two different outputs
Output 1 :
Values :
Ouptut 2 :
Values :
5
I've found some resources where its mentioned to pass integers to streams by converting to strings using std::to_string (Converting integer to string in c++) . But I want to know what makes the two processes act differently in the same scenario. It feels like as if one of the process do some changes to the streams in a global state
c++ ostream
c++ ostream
asked Jan 3 at 9:33
BAdhiBAdhi
151215
asked Jan 3 at 9:33
BAdhiBAdhi
151215
asked Jan 3 at 9:33
BAdhiBAdhi
151215
asked Jan 3 at 9:33
BAdhiBAdhi
151215
asked Jan 3 at 9:33
BAdhiBAdhi
151215
151215
2
Without a Minimal, Complete, and Verifiable example it's impossible to help you (except to wildly guess). Please take some time to review how to ask good questions, as well as this question checklist.
– Some programmer dude
Jan 3 at 9:37
2
On Linux if two processes are trying to write to same file, result is undefined. If you append PID to file-name, you will get correct output.
– gjha
Jan 3 at 9:38
add a comment |
2
Without a Minimal, Complete, and Verifiable example it's impossible to help you (except to wildly guess). Please take some time to review how to ask good questions, as well as this question checklist.
– Some programmer dude
Jan 3 at 9:37
2
On Linux if two processes are trying to write to same file, result is undefined. If you append PID to file-name, you will get correct output.
– gjha
Jan 3 at 9:38
2
2
Without a Minimal, Complete, and Verifiable example it's impossible to help you (except to wildly guess). Please take some time to review how to ask good questions, as well as this question checklist.
– Some programmer dude
Jan 3 at 9:37
Without a Minimal, Complete, and Verifiable example it's impossible to help you (except to wildly guess). Please take some time to review how to ask good questions, as well as this question checklist.
– Some programmer dude
Jan 3 at 9:37
2
2
On Linux if two processes are trying to write to same file, result is undefined. If you append PID to file-name, you will get correct output.
– gjha
Jan 3 at 9:38
On Linux if two processes are trying to write to same file, result is undefined. If you append PID to file-name, you will get correct output.
– gjha
Jan 3 at 9:38
add a comment |
1 Answer
1
active
oldest
votes
Try running the two different processes in different directories. From what you've shown, more than likely, they both are trying to access the same file. This isn't something you can do. Check out this post which talks about why trying to use threads to open the same file twice at the same time doesn't work.
answered Jan 3 at 16:16
Dawson MooreDawson Moore
155
thanks for the reply. but these processes was run one after the other. So there wasnt a doubt about writing the same file concurrently
– BAdhi
Jan 3 at 16:36
Did you use the close function to make sure the first process doesn't keep the file open?
– Dawson Moore
Jan 3 at 16:42
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
Try running the two different processes in different directories. From what you've shown, more than likely, they both are trying to access the same file. This isn't something you can do. Check out this post which talks about why trying to use threads to open the same file twice at the same time doesn't work.
answered Jan 3 at 16:16
Dawson MooreDawson Moore
155
thanks for the reply. but these processes was run one after the other. So there wasnt a doubt about writing the same file concurrently
– BAdhi
Jan 3 at 16:36
Did you use the close function to make sure the first process doesn't keep the file open?
– Dawson Moore
Jan 3 at 16:42
add a comment |
Try running the two different processes in different directories. From what you've shown, more than likely, they both are trying to access the same file. This isn't something you can do. Check out this post which talks about why trying to use threads to open the same file twice at the same time doesn't work.
answered Jan 3 at 16:16
Dawson MooreDawson Moore
155
thanks for the reply. but these processes was run one after the other. So there wasnt a doubt about writing the same file concurrently
– BAdhi
Jan 3 at 16:36
Did you use the close function to make sure the first process doesn't keep the file open?
– Dawson Moore
Jan 3 at 16:42
add a comment |
Try running the two different processes in different directories. From what you've shown, more than likely, they both are trying to access the same file. This isn't something you can do. Check out this post which talks about why trying to use threads to open the same file twice at the same time doesn't work.
answered Jan 3 at 16:16
Dawson MooreDawson Moore
155
Try running the two different processes in different directories. From what you've shown, more than likely, they both are trying to access the same file. This isn't something you can do. Check out this post which talks about why trying to use threads to open the same file twice at the same time doesn't work.
answered Jan 3 at 16:16
Dawson MooreDawson Moore
155
answered Jan 3 at 16:16
Dawson MooreDawson Moore
155
answered Jan 3 at 16:16
Dawson MooreDawson Moore
155
answered Jan 3 at 16:16
Dawson MooreDawson Moore
155
155
thanks for the reply. but these processes was run one after the other. So there wasnt a doubt about writing the same file concurrently
– BAdhi
Jan 3 at 16:36
Did you use the close function to make sure the first process doesn't keep the file open?
– Dawson Moore
Jan 3 at 16:42
add a comment |
thanks for the reply. but these processes was run one after the other. So there wasnt a doubt about writing the same file concurrently
– BAdhi
Jan 3 at 16:36
Did you use the close function to make sure the first process doesn't keep the file open?
– Dawson Moore
Jan 3 at 16:42
thanks for the reply. but these processes was run one after the other. So there wasnt a doubt about writing the same file concurrently
– BAdhi
Jan 3 at 16:36
thanks for the reply. but these processes was run one after the other. So there wasnt a doubt about writing the same file concurrently
– BAdhi
Jan 3 at 16:36
Did you use the close function to make sure the first process doesn't keep the file open?
– Dawson Moore
Jan 3 at 16:42
Did you use the close function to make sure the first process doesn't keep the file open?
– Dawson Moore
Jan 3 at 16:42
add a comment |
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2
Without a Minimal, Complete, and Verifiable example it's impossible to help you (except to wildly guess). Please take some time to review how to ask good questions, as well as this question checklist.
– Some programmer dude
Jan 3 at 9:37
2
On Linux if two processes are trying to write to same file, result is undefined. If you append PID to file-name, you will get correct output.
– gjha
Jan 3 at 9:38